Centrifugal pump.



H. A. J. DE B. NACHENIUS.

CENTRIFUGAL PUMP.

APPLICATION FlLED JULY 14. 1916,

LQYJQL Patented Sept. 10, 1918.

2 SHEETSSHEET I.

H. A. J. DE B. NACHENIUS.

CENTRlF-UGAL PUMP.

APPLICATION men JULY 14. I9I6.

LWSQQL Patented se t. 10, 1918.

2 SHEETS-SHEET 2.

HENRI ARNOLD J'dHANNES DE BIJ'LL NACHENIUS, OF EMBLEM, NETHERLANDS,

0 NAAMLOOZE vn'mzroorscne'r wear comma", or Ht CENTRIFUGAL PUMP.

' Specification. of letters Patent.

Application filed. July 14, 1916. Serial No. 109,295.

To all whom it may concern:

Be it known that I, HENRI ARNOLD Jo- H'AnNEs DE BIJLL NACHENIUS, mechanical engmeer, residing atHaarlem, the Netherlands, have invented cert in new and useful Improvements in Centri gal Pumps, of which the following is a specification.

This invention relates to the centrifugal pumps, more particularly to pumps such as employed for pumping liquids mixed with gravel, sand, mud or the like.

As is well known in the use'of so called gravel pumps as also of centrifugal pumps employed for emptying hoppers and the like, great trouble is encountered owing to wear,

for which reason such pumps are provided with an exchangeable lining.

In order to allow for the impeller being brought into position, this lining, usually madam the shape of a centrifugal pump casmg, is either split perpendicularly to its axis or across a straight, broken or curved line through its axis or is provided with an' opening 1n the slde wall, in practice closed by means of a cover. In spite of the hard:

ness of the material of which such linings of gravel pumps are constructed, the grinding effect on the inner surface of the lining is so severe that the lining must be replaced after a short period of use.

Practice has proved that this grinding effeet is especially severe along the joints between the parts of which the lining is composed and that this grinding effect is about proportional to the square of the velocity of the li uid.

In t e pumps above referred to, in which the impeller is brought into the lining through an opening in the side wall, the joint between the cover'and the wall forms a circle of a somewhat larger diameter than the diameter of .the impeller, where the.

velocity of the liquid to be pumped is considerable, some feet per second.

- In all other well known constructions mentioned aborve the joints must necessarily pass a zone in which the velocityof the liquid is such that the grmding efiectis destructive on the lining.

The object of the present invention is the.-

construction of a pump in which these drawbacks are avoided. For this purpose the This zone will be at ornear the delivery I opening, because the velocity decreases considerably from the periphery of the bucket wheel to the circumference of the casing. The opening by way of which the impeller may be brought into position is accordingly so disposed that all the joints are arranged at the circumference adjacent to the delivery opening in the casing; infact the delivery opening itself may be arranged in the cover of the opening by way of which the impeller can be introduced into the casing. The delivery pipe connected to said opening maybe constructed so as to gradually increase 1n section to the size of this opening.

The velocity of the liquid in the delivery opening is only 19 to 13 feet per second, so

that the grinding effect in the neighborhood of this opening is very little indeed. Moreover, the joints of the cover are so arranged in relation to the direction of the flow that along the same the casing or lining is practically not subjected to wear.

The invention is illustrated inthe accompanying drawings.

Figurev 1 is a side view of a pump constructed according to the invention Fig. 2 is a vertical section across a plane through. the axis;. Fig. 3 shows a-pump of mod fied construction.

Referring toFigs. 1 and 2, the casing 3 is shown as being of the; form. generally used in connection with gravel pumps. The impeller 4 has a diameter indicated by the dimension line 6, which is shorter than the length of the opening'in the circumference of the casing, asindicated by the llne 'Z, such opening being closed by means of the cover 8 which also serves as a delivery connection. The opening is also wider than the impeller 4 so that the impeller can be introduced into and removed from the casi through this opening. The inner art 0 the impeller. communicates with t e suction pipe 11 through a fixed pipe 9 provided with a pack- 100 mg device constituted by an adjustable slide' rin 10.

- 'l he shaft is fixed into the impeller by means of a conical screw thread and the check plate 13. The impeller may of course 1% be otherwise fixed to the shaft in any other suitable manner, it bein important only that it shall be capable o passing through the opening covered by the casting 8 The annular casing of a gravel pump 110 PatentedSept.i,19i8.

constructed that they m y beva'dlusted-rela" velocity mixes partly with the slow flow in the delivery pipe 16 so that at this point the velocity is inconsiderable, resulting in but very little wear along the joint.

Owi to the fact that as a result of the pumps correct distribution of the velocity of 'the liquid cannot be obtained, the pump according to Fig. 3 is also suitable from a constructional point of view. In the case of the ump shown in Fig. 3 the circumference of tEe'casing merges evenly into the delivery pipe 17 so that the impeller is, so to say, introduced into the casingin a tangential or radial direction throughthe delivery open- 'in in the casing.

- he pumps illustrated in the drawings;

, are unlined. In each instance the casing is cast to the required dimensions and the connecting parts of the suction pipe and the parts belonging to the packing device areso tively to one another. The casing therefore requires no machining. Replacement of the casing is less costly and occupies less time Having now describe my invention, what I claim as newand desire to secure by Letters Patent is: I v

1. In a centrifugal pump, an impeller, a casing having an opening at its periphery large enough to permit theinsertionof said simple orm of casing required for gravel than renewal of a lining of the usual shape.

impeller, and 'acover for said opening, the line of the joint between said cover and casing, being entirely of the impeller. v

2. In a centrifugal pump, an impeller, a

casing having an opening at its periphery.

large enough to permit the insertion of said impeller, and a cover for said opening, the

line of joint at the inner wall of said casing between said cover and easing being entirely outside the periphery of"the impeller.-

3. In a centrifugal pump, an impeller, a

asing having an opening at its periphery large enough to permit the insertion'of said impeller, a cover forsaid opening, and a delivery branch in said cover, the line of the joint between said-cover and easing being outside of the periphery of the.

entirely impeller.

large enough to permit the insertion 0 said impeller, a eover'for said ening, and a delivery branch, of. gradua y decreasing outside of the periphery section outwardly, in said cover, the line of a 1 5f 4. In a centrifugal pump, an impeller, a casing having an opening at its periphery 

